AIRSTAGE Technical Service Guidance
Service Valve (Schrader) Leaks
Likely causes, field rectification and warranty position
Guidance for service ports accessed during installation, commissioning, maintenance or refrigerant recovery
Summary: Leaks at service (Schrader) valves commonly occur after gauges, charging hoses or recovery equipment have been connected or disconnected. The technician who last accessed the valve should leak-check the service port and correctly refit the sealing cap.
Qualified personnel only: Refrigerant-system work must be completed by an appropriately licensed technician using equipment suitable for the refrigerant and system pressure. Follow applicable safety requirements and the product service documentation.
Why This Happens
- Valve cores can be distorted or contaminated when service tools are inserted or removed.
- A missing or loose metal sealing cap with an intact gasket removes the valve's secondary seal and dirt barrier.
- Dirt under the core seat, damaged seals or overtightening the valve core can cause a slow refrigerant leak.
Recommended Field Procedure
1. Make the system safe
- Isolate electrical power and identify the leaking service port.
- Where the system remains charged, use a core-removal tool specifically rated for replacement under pressure.
2. Replace the valve core
- Fit the core-removal tool, verify shut-off and remove the existing core.
- Inspect the valve seat and remove any debris.
- Install a new HVAC-rated core. Tighten it only sufficiently to seal; do not overtighten.
3. Reinstate the secondary seal
Fit a metal sealing cap with an intact gasket. Tighten it firmly in accordance with the applicable service instructions. The cap provides the long-term secondary seal and protects the service port from contamination.
4. Leak-test the repair
- Where pressure testing is required, use dry nitrogen and follow the manufacturer's specified test pressure and procedure.
- Apply an approved leak-detection solution to the valve core, service-port body and sealing cap.
- Confirm there is no pressure loss or evidence of leakage during the required test period.
5. Evacuate and recharge where the circuit was opened
- Evacuate the system to the level specified in the applicable service documentation and confirm an acceptable standing-vacuum result.
- Charge the correct refrigerant by weight and verify final operating conditions.
6. Document the work
Record the valve location, component replaced, test pressure, vacuum result, refrigerant added or recovered, and final operating readings on the job card.
Preventive Practices
| Practice | Required action |
|---|---|
| Refit the sealing cap | Always reinstall the correct metal cap with its gasket after accessing the service port. |
| Keep ports clean | Prevent dirt and moisture from entering the valve and use service hoses with depressors in good condition. |
| Minimise valve wear | Do not leave gauges connected unnecessarily. Use suitable low-loss or quick-connect fittings where appropriate. |
| Include in maintenance | Check service-port cores and sealing caps during routine maintenance and whenever gauges are removed. |
Warranty Position
Leaks arising from service-port access after installation are generally treated as a service or maintenance rectification, rather than a manufacturing defect. The installer or service contractor who accessed the valve should inspect and rectify the leak.
- The technician who last connected gauges or recovery equipment is responsible for checking the service port for leakage.
- The sealing cap must be reinstated correctly after service access.
- Warranty assessment remains subject to inspection, the product warranty terms and the circumstances of the reported failure.
Always confirm test pressures, evacuation requirements, tightening requirements and refrigerant procedures against the applicable product installation and service documentation.